The Effect of a Moderate Zinc Deficiency and Dietary Fat Source on the Activity and Expression of the Δ3Δ2-Enoyl-CoA Isomerase in the Liver of Growing Rats

Abstract

Auxiliary enzymes participate in β-oxidation of unsaturated fatty acids. The objective of the study was to investigate the impact of a moderate zinc deficiency and a high intake of polyunsaturated fat on Δ(3)Δ(2)-enoyl-CoA isomerase (ECI) in the liver and other tissues. Five groups of eight weanling rats each were fed moderately zinc-deficient (ZD) or zinc-adequate (ZA) semisynthetic diets (7 or 50 mg Zn/kg) enriched with 22 % cocoa butter (CB) or 22 % safflower oil (SO) for 4 weeks: (1) ZD-CB, fed free choice; (2) ZA-CBR, ZA-CB diet fed in equivalent amounts consumed by the ZD-CB group; (3) ZD-SO, fed free choice; (4) ZA-SOR, ZA-SO diet fed in equivalent amounts consumed by the ZD-SO group; and (5) ZA-SO, fed free choice. Growth and Zn status markers were markedly reduced in the ZD groups. ECI activity in the liver of the animals fed the ZD- and ZA-SO diets were significantly higher (approximately 2- and 3-fold, respectively) as compared with the CB-fed animals, whereas activities in extrahepatic tissues (kidneys, heart, skeletal muscle, testes, adipose tissue) were not altered by dietary treatments. Transcript levels of the mitochondrial Eci gene in the liver did not significantly differ between ZD and ZA rats, but were 1.6-fold higher in the ZA-SO- than in the ZD-CB-fed animals (P < 0.05). It is concluded that diets enriched with safflower oil as a source high in linoleic acid induce markedly increased hepatic ECI activities and that a moderate Zn deficiency does not affect transcription of the mitochondrial Eci gene in the liver.

A Moderate Zinc Deficiency Does Not Alter Lipid and Fatty Acid Composition in the Liver of Weanling Rats Fed Diets Rich in Cocoa Butter or Safflower Oil

“…Thus, with fat being the major energy source in the present experiment (55 to 60% of the energy intake), it is reasonable to assume that body FAs were essentially of dietary origin, with alterations resulting from ß-oxidation and chain modifications. Numerous animal studies found that Zn deficiency per se does not impede ß-oxidation of FAs, including unsaturated FAs (reviewed in [40]). Likewise, there is ample evidence that Zn depletion does not hinder chain desaturation and elongation of linoleic acid and α -linolenic acid (reviewed in [41]).…”

Zinc transporter 7 deficiency affects lipid synthesis in adipocytes by inhibiting insulin‐dependent Akt activation and glucose uptake

“…Liver linoleic acid levels are high in zinc deficient rats due to low activities of zinc‐dependent Δ6‐ and Δ5‐desaturases that convert linoleic acid to γ‐linoleic acid and then to arachidonic acid . In the rat liver, zinc deficiency suppresses the activity of Δ3,Δ2‐enoyl‐CoA isomerase, an auxiliary enzyme removing the double bond of unsaturated fatty acids prior to β‐oxidation, resulting in linoleic acid and arachidonic acid accumulation in adipose tissue .…”

Cloning, expression, and polymorphism of the ECI1 gene in various pig breeds

“…It has also been shown that ECI1-deficient mice develop dicarboxylic aciduria and exhibit hepatic accumulation of lipids with unsaturated fatty acyl groups (Janssen and Stoffel 2002). Furthermore, rodent diets enriched with safflower oil (a source high in the unsaturated linoleic fatty acid) induced a marked increase in hepatic ECI activities (Justus and Weigand 2014b). However, the role of ECI1 in pig adipose tissue deposition remains poorly understood, and to date, little information about the pig ECI1 gene exists.…”